TABLE 3.
Analysis of class 1 and class 2 integrons and their resistance gene cassettes in the 17 multiresistant E. coli strains
| E. coli strain (origin)a | Class 1 integron
|
Class 2 integron
|
|||||
|---|---|---|---|---|---|---|---|
| Detection ofb:
|
Variable region amplified by PCR
|
Detection of intI2 geneb | Variable region amplified by PCR
|
||||
| intI1 | qacEΔ1 sul1 | Size of amplicons obtained (bp) | Genes included in cassettes | Size of amplicons obtained (bp) | Genes included in cassettes | ||
| Co1 (F) | − | − | NADc | + | 2,000 | dfrA1 + sat + aadA1 | |
| Co19 (F) | − | − | NAD | + | 2,000 | dfrA1 + sat + aadA1 | |
| Co45 (F) | − | − | NAD | + | 2,000 | dfrA1 + sat + aadA1 | |
| Co53 (F) | − | − | NAD | − | NAD | ||
| Co71 (B) | + | + | 1,700 | dfrA17 + aadA5 | − | NAD | |
| Co80 (B) | + | + | 1,000 | aadA1 | − | NAD | |
| Co82 (B) | + | + | 1,700 | dfrA17 + aadA5 | − | NAD | |
| Co110 (B) | + | + | 1,500 | dfrA1 + aadA1 | − | NAD | |
| Co125 (P) | + | − | NAD | dfrA12 + orfF + aadA2d | + | 2,000 | dfrA1-like + sat + aadA1 |
| Co279 (P) | − | − | NAD | − | NAD | ||
| Co177 (D) | + | + | 1,500 | dfrA1 + aadA1 | − | NAD | |
| Co201 (D) | + | + | 1,500 | dfrA1 + aadA1 | − | NAD | |
| Co227 (H) | + | + | 1,500, 2,000 | dfrA1 + aadA1, dfrA12 + orfF + aadA2 | − | NAD | |
| Co228 (H) | + | + | 2,000 | dfrA12 + orfF + aadA2 | − | NAD | |
| Co232 (H) | + | + | 1,500 | dfrA1 + aadA1 | − | NAD | |
| Co354 (H) | + | + | 1,500, 2,000 | dfrA1 + aadA1, dfrA12 + orfF + aadA2 | − | NAD | |
| Co356 (H) | + | + | 1,700 | dfrA17 + aadA5 | − | NAD | |
a
F, food; B, broiler; P, pig; D, dog; H, human.
b
+, detected; −, not detected.
c
NAD, No amplicon was detected.
d
These gene cassettes were detected by sequencing of amplicons obtained with the primers Int-F and AadA-R.